Effect of maternal corticosteroid provision on middle cerebral artery peak systolic velocity readings in the potentially anaemic fetus prior to planned intrauterine transfusion

Purpose Middle Cerebral Artery Peak Systolic Velocity ( MCA ‐ PSV ) is the main tool for determining need for and timing of intrauterine transfusions ( IUT ) for severe fetal anaemia. It has been suggested that steroids temporarily decrease MCA ‐ PSV , potentially increasing false‐negative MCA ‐ PSV findings in anaemic fetuses. We therefore aimed to assess whether maternal corticosteroid administration prior to IUT is associated with clinically significant temporary decreases in MCA ‐ PSV . Methods Retrospective review 2005–2016 of steroid provision prior to IUT , with correlation of MCA ‐ PSV pre‐ and post‐steroid administration and haemoglobin at IUT . Results In 23 identified cases, there was no significant difference between average MoM pre‐ and post‐steroid (1.71 ± 0.41 vs. 1.66 ± 0.38, −2.9% mean, P = 0.4). There was also no significant difference between pre‐ and post‐steroid MoM taken within 3 days of each other (n = 19, P = 0.21). However, post‐steroid MCA ‐ PSV decreased by >15% in 6/23 cases (A‐B zone in two cases, B‐C zone in one case). Conclusions This study found no sizeable, generalised effect of corticosteroid administration on MCA ‐ PSV readings in the potentially anaemic fetus. A minority showed substantial shifts where reliance on post‐steroid MCA ‐ PSV could have unfavourably altered clinical management. Ultimately, further large‐scale research is required before we can discount the potential impact of steroids on MCA ‐ PSV values.